Season by Season Highlights:
Winter Season (December 1, 2002 through February 28, 2003):
Temperatures -- The winter season featured above-normal average temperatures during December, but turned colder than normal for January and February. Significant cold periods occurred during the middle of January, and toward the end of February. High temperatures on January 23rd stayed in the single digits in many areas.
Weather -- The year started out very snowy in portions of central Illinois, where 6 to 10 inches of snow accumulated from Lewistown to Jacksonville, and also near Danville.
The most unusual occurrence was on the evening of February 11th. Severe thunderstorms accompanied snow squalls, causing some tree and power line damage across Marshall, Woodford, Peoria and Tazewell Counties. As the associated frontal boundary passed through Illinois, bringing strong winds for a period, spontaneous "snowballs" developed along the ground. These snow rollers ranged from the size of golfballs to as large as a foot high and 30 inches long, and were reported well east into Indiana and Ohio.
Spring Season (March 1 through May 31):
Temperatures -- Overall during the period, temperatures were close to long-term averages. The first several days of March, as well as much of May, featured temperatures well below normal. Temperatures did not reach 90 degrees during the period.
Weather -- By far, the most significant weather was in May. The 35 counties covered by the Lincoln NWS office reported a total of 41 tornadoes, more than doubling the previous record of 20 set in May 1995. These were among 126 tornadoes which occurred across Illinois during 2003, breaking the old record of 107 set in 1974.
The most active day was on May 10. Two separate severe weather outbreaks occurred. The first one was in the morning, and mainly affected areas along and south of the I-72 corridor. The second one was concentrated in the Illinois River valley, and produced a strong and long-track tornado from South Pekin to Morton, which injured 32 people.
Other weather highlights during the period included the year's first tornado in central Illinois on March 19 in Sangamon County, a downburst which produced 100 mph winds in the northwest part of Lincoln on April 4, and a pair of strong tornadoes on May 30 tracking from near Lincoln to Clinton, causing $10 million damage.
Fairly dry weather was noted in March and April, but May was wetter than normal across much of the eastern half of the state. Lawrenceville reported a total of 10.18 inches of rain during May.
Summer Season (June 1 through August 31):
Temperatures -- Temperatures averaged significantly below normal during June, but rebounded to above normal during August. The first few days of June saw temperatures 10 to 20 degrees below normal; Springfield noted its coldest June temperature on record (39 degrees) on June 1st. Significant warm spells included July 3 through 8, and also during the middle and latter parts of August.
Weather -- Several weak tornadoes touched down the evening of June 11, primarily within an area bounded by Springfield, Lincoln, Clinton and Decatur. These severe thunderstorms also caused localized flash flooding.
Severe thunderstorms on July 8 produced an 88 mph wind gust in Bloomington, downing several large trees and power lines. A brief tornado touched down southwest of Pekin near the Powerton plant, but did not cause any injuries. The next day, another round of severe weather produced flash flooding in parts of central Illinois. Lincoln reported 4.78 inches of rain, its greatest 24-hour total on record. Two-day rainfall totals ending the morning of July 10 showed widespread totals over 7 inches from I-155 to the Bloomington/Normal area.
Severe thunderstorms on August 3 produced downburst winds around 70 mph in downtown Decatur. This led to large-scale evacuations at the Decatur Celebration held outdoors, but only 5 people were injured.
Autumn Season (September 1 through November 30):
Temperatures -- September featured temperatures averaging below normal across Illinois. Temperatures were closer to long-term averages during October, with warmer than normal temperatures for November. The first freeze of the season occurred earlier than normal in most locations (late September or early October), but locations south of I-70 did not freeze until November.
Weather -- Precipitation was above normal during September, especially near the I-72 corridor. Much of this heavy rain occurred over the Labor Day weekend. The heaviest rainfall was between Pana and Danville. A total of 10.02 inches of rain occurred in Bismarck (Vermilion County) during this period, with over 7 inches around Sullivan and from Urbana northeast to the Indiana border.
Heavy rainfall occurred in some areas on November 17-18. Champaign/Urbana reported 2.87 inches during this period, with Springfield reporting 2.74 inches, and the Decatur Airport 2.71 inches.
Winter season to date (December 1 to 17, 2003):
Temperatures -- Temperatures were above normal for the first several days of December, before a cooling trend set in by the 11th. The warmest weather occurred on the 9th and 10th, as temperatures reached the 50s in many areas.
Weather -- On December 5, the first significant snowfall of the season occurred. Although totals were only 1 to 3 inches, it was enough to get people re-acquainted with winter driving. More substantial snowfall occurred on December 13th. The heaviest snowfall in this period was across Fulton and western Mason Counties, where totals of 5 to 6 inches were reported.
Statistics for the 35-county Lincoln NWS coverage area: